Let the distance between station A and B = ab Km
Let the distance between station B and C = bc Km
Then (ab/80) Km is the amount of time taken in hours the train took to travel from station A to B.
Also, (bc/60)Km is the amount of time taken in hours the train took to travel from station B to C.

$$We\ now\ have\ to\ find\ the\ value\ of\ \frac{\left(ab+bc\right)}{\frac{ab}{80}+\frac{bc}{60}}$$

Statement 1: The distance that the train traveled from Station A to B was 4 times the distance the train
traveled from B to C.
$$Therefore,\ \frac{\left(ab+bc\right)}{\frac{ab}{80}+\frac{bc}{60}}=\frac{\left(4bc+\ bc\right)}{\frac{4bc}{80}+\frac{bc}{60}}=\frac{\left[bc\left(4+1\right)\right]}{bc\left(\frac{4}{80}+\frac{1}{60}\right)}$$
$$=\frac{\left(4+1\right)}{\frac{4}{80}+\frac{1}{60}}$$
We can get a definite value here. hence, statement 1 is sufficient

Statement 2: The amount of time it took the train to travel from station A to B is 3 times the amount of time taken it took the train to travel from station B to C
$$Therefore,\ \frac{ab}{80}=3\ \left(\frac{bc}{60}\right)$$
$$\frac{ab}{80}=\frac{bc}{20}$$
$$by\ cross\ multiplying,\ we\ have$$
$$20ab=80bc$$
$$In\ ratio\ of\ ab=4bc\ which\ is\ the\ same\ with\ statement\ 1.\ Hence,\ statement\ 2\ is\ sufficient$$

In conclusion, OPTION D is correct because each of statement 1 and 2 is sufficient alone